A wide range of electronic hardware requires the use of multiple circuit boards having electronic devices mounted thereon. In order to minimize space, such devices typically comprise a plurality of boards mounted in a side by side relationship within a chassis. The boards are designed to be individually removable from the chassis to allow them to be tested, repaired or replaced with updated circuitry if desired.
Because of the close spacing between individual circuit boards mounted in a chassis, it is often difficult to grip an individual circuit board with the requisite strength required to withdraw it from the chassis. In order to overcome this problem, circuit boards have been provided with various mechanisms designed to allow a technician to grip the circuit board with sufficient strength to remove it from its mounting. The earliest attempts to overcome this problem comprised simply of providing small handles mounted on the exposed edge of the circuit board. Although these handles are still used and remain useful in removing closely spaced circuit boards from a chassis, they did not address the additional problem of providing a secure mount for the circuit board within the chassis.
In numerous high performance applications such as avionics and military hardware, the chassis mounting the circuit boards is subjected to a high degree of motion and vibration. These forces may cause a circuit board to be shaken free of its mounting position, and ultimately free of electrical contact with the chassis and the remaining circuitry. Such a result may have catastrophic consequences causing either the loss of necessary function of the electronic device, or the failure of the device in its entirety.
To address the issue of undesired release, circuit boards have been provided with injector/extractor mechanisms. These mechanisms typically comprise a lever mounted on the edge of a circuit board near its upper or lower corner. The lever is mounted to the circuit board using a pivot pin which allows the lever to pivot from a first position, flush with an edge of the circuit board, to a second position which provides a handle for pulling and removing the circuit board from the chassis. Additionally, such injector/extractors often include a section positioned on the opposing side of the pivot pin which engages the chassis within which the circuit board is mounted and acts either as a fulcrum to either pull the circuit board from its mounted position or as an interference member to maintain the circuit board within its mount.
Although the injectors/extractors described above represent a significant improvement over the earlier circuit board handles, their performance is less than ideal as they are still subject to vibrational motion and the possibility of inadvertent release. Additionally, due to the lever nature of such devices, it is relatively easy for such devices to accidentally release by becoming snagged on a technician's clothing, tools, or work materials. As with vibratory release, if the condition remains undetected, failure of the electronic hardware will likely result.
In view of the above, a need exists for an injector/extractor that allows a circuit board to be easily locked into or released from a chassis and also which is not likely to release when subjected to vibration or snagging. It is also desirable that such a device be simple to manufacture and use. In addition, a need exists for an injector/extractor device having means for visually indicating that a circuit board is properly locked within its chassis.